The present invention relates to heterodyne millimeter wave radar systems, and more particularly, to a low cost collision avoidance sensor and radar for use in automotive speed and collision avoidance systems.
The assignee of the present invention develops automotive cruise control and collision avoidance systems, and the like. As a result of angular resolution requirements and antenna size limitations, development relating to automotive cruise control and collision avoidance applications has been performed in the 75 to 95 GHz frequency band. Due to the maturity of the technology used at these shorter wavelengths, the majority of the system hardware at these wavelengths uses conventional waveguide transmission and cavity techniques.
However, waveguide components, manufactured in any form, are limited in how inexpensively they can be produced in high volume production. In addition, given the requirements for less than 2 degree resolution and 30 degree azimuth coverage, heretofore, a narrow beam mechanically scanned antenna has been the only available option. For many reasons a gimbled flapping (mechanically scanned) antenna does not provide an optimum solution.
Another approach that might be adapted for use in the 75 to 95 GHz frequency band, seldom mentioned due to the present state-of-the-art, is a slotted waveguide phased array antenna. This antenna, with its electronically scanned beam capability, works well at lower frequencies, but has a number of limitations in the 75 to 95 GHz band. These limitations include degraded electrical performance and very high cost even in high production quantities.
Therefore, it is an objective of the present invention to provide for a heterodyne millimeter wave radar system employing a low cost sensor, or RF camera, for use in automotive speed and collision avoidance systems, and the like.